Embodiments of the present invention relates generally to switches for use in motor vehicles and, more particularly, to vehicle switches having a self-identifying switch function. The self-identifying feature of the switches enables the placement of switches in any of a number of locations consistent with a customer's desired switch customization requirement, while providing for the identification of a switch regardless of its location, such that switches can be placed in any position within a defined network on the vehicle without changing the switch's functionality or the system wiring.
Additional embodiments of the present invention relate generally to electrical control switches and, more particularly, to control switches in contactors and motor starters having a radio frequency identification (RFID) tag incorporated therein. The incorporation of an RFID tag into a motor starter/contactor switch provides for an accurate determination of the position of contacts in the motor starter/contactor.
Electrical switches are used in motor vehicles as control switches for switching the motor vehicle lighting, the windshield wipers, the rear windshield heating, the cruise control functions, the internal central locking and other functions on and off. A number of such switches can be combined as control panels in the dashboard, in the center console or the like. In specialty vehicle markets—such as heavy trucks, agricultural equipment, and construction equipment, for example—many original equipment manufacturers (OEMs) produce custom dashboards for their customers. In doing so, the OEMs allow the customers to pick options as well as their associated switch locations. While such customization is desirable from the standpoint of the customer, such customization leads to significant overhead expenses for the OEMs with respect to managing customer options for the dashboards. That is, present methods of managing production for customer dashboards having customized options and associated switch locations requires separate drawings and wire harnesses for every vehicle manufactured. Furthermore, some OEMs may even install the wires for every option sold, but only connect the wires used with the individual customer dashboard order.
In the mix of switch functions, some switches provide input signals to a vehicle's microprocessor-based controller, often referred to as a body controller, or electronic controller unit (ECU), which receives the signal and makes logic decisions regarding how that function is to be performed or activated. Other switches are wired directly to their intended loads. Those switches providing an ECU input typically operate at very low current, typically in the range of 5 to 20 milliAmperes (mA), whereas direct-wired switches may handle loads up to 20 Amperes or more. Different contact materials are needed to accommodate these varying load ranges, as well as different sized wires and connectors. The arrangement or rearrangement of switches within the dashboard array is often limited in practice by the ability of the OEM to provide appropriate high current and low current wiring to support the desired functions. It is also common for OEMs to provide the same type of electrical connector and wires for all switch positions for economy and standardization, though the practice can result in a higher percentage of wiring errors at the time the vehicle is being assembled.
It is recognized that electrical control switches may be utilized in other environments beyond that of vehicle controls. One such alternative environment in which electrical control switches are utilized is in electromagnetic contactors and motor starters. Contactors are generally used in motor starter applications to switch on/off a load as well as to protect a load, such as a motor, or other electrical devices from current overloading. As such, a typical contactor has three contact assemblies—a contact assembly for each phase or pole of a three-phase electrical device. Each contact assembly, in turn, includes a pair of stationary contacts and a pair of moveable contacts. One stationary contact will be a line side contact and the other stationary contact will be a load side contact. The moveable contacts are controlled by an actuating assembly comprising a contact carrier and an armature magnet assembly which is energized by a coil to move the moveable contacts to form a bridge between the stationary contacts. When the moveable contacts are engaged with both stationary contacts, current is allowed to travel from the power source or line to the load or electrical device. When the moveable contact is separated from the stationary contacts, an open circuit is created and the line and load are electrically isolated from one another.
In operation of a motor starter/contactor, it is recognized the state of the contactor (opened or closed) is often needed but does not always correlate to the actuating coil being energized. The contactor can remain opened even though energy is applied to the coil due to failure of the coil itself or the movable contact assembly becoming jammed due to debris or other mechanical interference. Likewise, the contactor can remain closed even though energy has been removed from the coil due to contact welding or mechanical jamming of the movable contact assembly. The standard industry practice to definitively know the state of the contactor is to use an auxiliary contactor which is mechanically linked to the moving contactor assembly of the primary contactor. As the primary contactor moves as it opens and closes, the auxiliary contactor will likewise open and close.
While auxiliary contactors provide an effective means for determining the state of the contactor, it is recognized that the use of such auxiliary contactors are not without drawbacks. First, the auxiliary contactors are an accessory in most motor starters/contactors on the market due to the added cost of additional contactors. Second, the use of auxiliary contactors requires more wiring and additional control inputs, which also increases cost. This burden is compounded in the case of reversers where separate starters are required for energizing a motor to run in each of two directions, and in two-speed motors where separate starters are required for energizing the low speed coil and the high speed coil of the motor.
It would therefore be desirable to design a system that enables OEMs to reduce the cost of managing a custom dashboard. In doing so, the system and method would allow for dashboard customization without requiring the OEM to rewire/relocate the wire harnesses to accommodate the customization—thereby enabling vehicle OEMs to significantly reduce the engineering overhead and the wire count associated with a custom dashboard.
It would also therefore be desirable to provide a means for determining the state of a contactor that can be performed despite failure of the actuating coil, contact welding of the contacts, or the movable contact assembly becoming jammed due to debris or other mechanical interference, and without the need for any auxiliary contactor mechanically linked to the moving contactor assembly of the primary contactor and any associated wiring and equipment to determine the electrical state of the auxiliary contactor, therefore reducing the cost and complexity of the contactor.